Understanding and controlling the coherence of quantum spins in solid-state systems is crucial in areas such as precision metrology, quantum information science, and quantum many-body dynamics. A main source of decoherence for solid-state spin systems, such as defects in diamond, donors in silicon, and quantum dots, is the uncontrolled spin bath environment. Control of spin bath dynamics is a key challenge in practical applications, which include magnetometry and room temperature quantum computing.
For precision coherent measurements with ensembles of quantum spins the relevant Figure-of-Merit (FOM) is the product of spin density and coherence lifetime (T2), which is generally limited by the dynamics of spin coupling to the environment. Significant effort has been invested in understanding the causes of decoherence in a diverse range of spin systems in order to increase the FOM and improve measurement sensitivity.